CN111203172B - Method for preparing heavy metal adsorbent by recycling waste lithium ion battery anode material - Google Patents

Abstract

A method for preparing a heavy metal adsorbent by recycling waste lithium-ion battery anode materials, comprising the following steps: (1) dismantling waste lithium-ion batteries, and unrolling aluminum foil into rolls; (2) recycling the disassembled lithium-ion battery cathode materials And obtain the water heavy metal adsorbent precursor material; (3) Modification of the adsorbent precursor material. The heavy metal adsorbent prepared by the above method is used for adsorption treatment of Cu, Cd, Zn or Pb heavy metal polluted water body, and can regenerate the adsorbent. The present invention broadens the resource utilization approach of waste lithium-ion batteries. From the perspective of "treating waste with waste", based on the special crystal structure properties of metal oxides in the positive electrode of waste lithium-ion batteries, through the recovery and treatment of positive electrode materials, the It is used as a heavy metal adsorbent for polluting water bodies, and there are no related methods and application reports.

Description

Method for preparing heavy metal adsorbent by recycling waste lithium-ion battery cathode material

technical field

The invention relates to a method for preparing a water heavy metal adsorbent by recycling positive electrode materials of waste lithium ion batteries, and belongs to the technical field of water heavy metal adsorbent preparation.

Background technique

After being ingested by the human body, heavy metals not only exist in the form of ions, but also combine with macromolecular compounds such as proteins and fats in the body to form chelates with higher toxicity. Heavy metals in polluted water (such as mercury, lead, copper, zinc, cadmium, etc.) have the characteristics of bioaccumulation, persistence, and amplification, and are currently one of the ecological and environmental issues that have attracted widespread attention.

At present, the commonly used methods for the treatment of heavy metal pollution in water include chemical precipitation, electrolysis, ion exchange, and heavy metal ion adsorption. Although the precipitation method is simple to operate and widely used, it has certain limitations in use. It can only be applied to heavy metal ions (such as lead, silver, iron, copper, manganese, etc.) that can form water-insoluble precipitation substances with the precipitant, and Added chemical substances are likely to cause secondary pollution. The electrolysis method is to reduce the heavy metal ions through a chemical reaction in the electrolytic cell, and the obtained heavy metal element is deposited on the cathode or anode, thereby removing heavy metal pollutants in the water body. However, when the amount of wastewater to be treated is large, the power consumption and electrode metal consumption are large, and the separated precipitates are not easy to process and utilize. The ion exchange method is based on the principle of ion exchange, and the heavy metal ions that need to be removed are exchanged from the water to achieve the purpose of removing heavy metal ions in the water. However, the ion exchange method often produces waste liquid in the process of treating wastewater, and consumes a lot of ion exchangers, resulting in high operating costs.

Adsorption method is a method of removing heavy metal ions in water by adsorption of adsorbents with large specific surface area and special internal structure. Common adsorbents include activated carbon and inorganic ceramsite adsorbents, but such adsorbents are expensive to use and difficult to regenerate.

In recent years, with the increasing shortage of fossil resources in the world and the urgent need for ecological environment protection, the development of electric vehicles to replace fuel vehicles has attracted widespread attention. The rapid development of the power battery industry, especially the mass production and wide application of lithium-ion batteries has led to a surge in the number of waste batteries. If the waste lithium-ion batteries cannot be disposed of in a timely, effective and reasonable manner, it will cause serious waste of resources and cause environmental problems. The current development of the lithium-ion battery industry is facing a problem that has to be solved: the rational use of waste lithium-ion batteries and disposal.

At present, the treatment of waste lithium-ion batteries is to recover the heavy metals in the positive electrode through acid leaching, bioleaching, solvent extraction, chemical precipitation and electrochemical treatment. pollution etc.

CN110563046A discloses a method for recovering positive electrode materials of waste lithium ion batteries. In the method, the positive electrode materials separated from waste lithium ion batteries are sequentially subjected to mixed organic acid treatment, solid-liquid separation, solid collection, washing, drying, crushing, and calcining , the obtained positive electrode active material manganese oxide. However, the recycling process is complicated, especially the calcination section takes a long time and the recycling cost is high.

CN110144461A discloses a method for comprehensively recovering positive pole pieces of waste lithium-ion batteries. The positive pole leftovers and scrap positive pole pieces are put into a vacuum furnace for calcining, then vibrated and sieved to obtain positive pole active materials, and then the positive pole active materials are added to the sulfuric acid leaching solution Carry out two-stage leaching, filter and separate to obtain leaching residue carbon and leaching solution containing nickel, cobalt, manganese and lithium; add activated carbon to the leaching solution for adsorption deoiling and silicon removal, and add nickel carbonate, cobalt carbonate, manganese carbonate or carbonic acid to the filter residue The lithium is obtained as a precursor, and the precursor is ball milled, sintered, pulverized, ground, and sieved to obtain a nickel-cobalt lithium manganate positive electrode material. The recovery process of the positive electrode sheet of the waste lithium-ion battery is complicated, the cost is high, acid-base extraction is required, and secondary pollution is likely to occur.

Contents of the invention

In view of the current situation that the recycling method of waste lithium-ion batteries is single and the recycling cost is high. Starting from the perspective of "using waste to treat waste and turning waste into treasure", the present invention provides a method with simple process, low cost and good utilization effect to recycle the positive electrode material of waste lithium ion battery to prepare heavy metal adsorbent, which can realize the recovery of waste lithium The cathode material of the ion battery is recycled and used as an adsorbent for heavy metals in water.

The present invention reclaims the method for preparing the heavy metal adsorbent from waste lithium-ion battery anode materials, comprising the following steps:

(1) Dismantling of waste lithium-ion batteries:

Obtain the battery pack from the shell of the waste lithium-ion battery, take out the connecting wires and solder joints of the battery pack to obtain a lithium-ion battery; discharge each battery; then put the discharged lithium-ion battery into a saturated NaCl solution, Short-circuit the positive and negative poles of the lithium-ion battery monomer, and finally fully discharge the lithium-ion single battery, then disassemble the single battery, unroll the aluminum foil in a roll, and the attachment (black solid attachment) on the aluminum foil is the lithium-ion battery positive electrode material;

The process of discharging each single cell is: connect the positive and negative electrodes of each single cell to a 3-5W small light bulb to discharge until the small light bulb goes out (not bright).

The full discharge of the single cell refers to detecting the voltage of the discharged lithium ion single cell to ensure that the single cell voltage is less than 0.3V (that is, the discharge process is considered to be over).

The process of dismantling the single battery is to cut off the sealing ring of the positive terminal of the battery, remove the top gasket, cut off the aluminum shell wrapped outside, tear off the transparent film, and unfold the aluminum foil into a roll. It is the positive electrode active material (metal oxide material) of the lithium-ion battery.

(2) Recycling of lithium-ion battery cathode materials obtained from dismantling:

Cut the expanded aluminum foil with the positive active material into pieces, immerse in dimethyl sulfoxide (DMSO), shake at a constant temperature in a water bath, and dissolve the electrode binder (polyvinylidene fluoride (PVDF)) in dimethyl sulfoxide (DMSO). sulfone, and then microwave ultrasonic treatment to completely separate the positive electrode active material on the aluminum foil, take out the aluminum foil and rinse it with clean water to obtain a clean aluminum foil;

After the aluminum foil is taken out, the dimethyl sulfoxide mixed solution dissolved with the electrode binder is shaken under the condition of maintaining a constant temperature of 80±5°C in a water bath, and filtered through a filter membrane with a pore size of 0.45 μm to obtain the positive electrode active material (filter cut-off substance) , washing the positive electrode active material successively with 70% ethanol and deionized water, drying to obtain the water heavy metal adsorbent precursor material;

The side length of the fragments is 0.2-1 cm. The mass ratio of the fragments to dimethyl sulfoxide is 1:10-15. The shaking time is 1-2 hours. The microwave ultrasonication time is 10-30 minutes. The drying temperature is 80-100°C.

Since the solubility of PVDF in DMSO decreases at low temperature, the filtered mixed solution is left to cool to 0-10°C. If PVDF exceeds the saturation in the mixed solution, PVDF will precipitate from the solvent, and then filter with a filter membrane with a pore size of 0.45 μm Separation and recovery of PVDF, the separated DMSO mixed solution can continue to be returned to the front end of the process as a solvent for PVDF in the electrode active material; if the PVDF in the mixed solution does not exceed saturation, the mixed solution can be directly returned to the front end of the process as an electrode active material The solvent of PVDF in the material is recycled for the recovery of electrode active materials.

(3) Modification of adsorbent precursor material:

At room temperature, add the obtained water heavy metal adsorbent precursor material into a DTPA (diethyltriaminepentaacetic acid) solution with a mass concentration of 0.1%, and perform ultrasonic treatment to form a uniformly dispersed precursor material mixture;

Slowly drop the precursor material mixture into the alkaline solution of glutaraldehyde, react at room temperature, wash the obtained static precipitation product with deionized water and ethanol, and dry to obtain the modified water heavy metal adsorbent.

The water heavy metal adsorbent precursor material is added to the DTPA solution at a mass volume ratio of 1 g: 5 ml. The ultrasonic time is 10-30 minutes. The precursor material mixture is added to the alkaline solution of glutaraldehyde at a volume ratio of 1:4-5. The alkaline solution of glutaraldehyde is prepared by mixing 20-30% glutaraldehyde solution and 0.01M NaOH at a volume ratio of 1:20-30. The reaction time at room temperature is 10-12 hours. The drying is oven drying at 60-80° C. for 24 hours.

The heavy metal adsorbent prepared by the above method is used for adsorption and treatment of Cu, Cd, Zn or Pb heavy metal polluted water:

For industrial wastewater involving heavy metals, during static adsorption, first adjust the pH of the wastewater to 6-8, and determine the dosage of the adsorbent according to the concentration of heavy metals in the water: ① Heavy metals in water Cu ²⁺ , Pb ²⁺ , Cd ²⁺ or Zn ²⁺ When the concentration is lower than 50mg/L, the adsorbent is added to the water body at a ratio of 1g:1000ml (when the adsorption balance is reached, the removal rates of the four metals in the water body can reach 85%, 85%, 50%, and 50% or more respectively) ;② When the concentration of heavy metal Cu ²⁺ , Pb ²⁺ , Cd ²⁺ or Zn ²⁺ in water is 50-100mg/L, the adsorbent is added to the water body in the ratio of 1g:500ml (after the adsorption equilibrium is reached, the four kinds of water bodies The removal rate of metal can reach 85%, 85%, 60%, 50% or more); ③ when the concentration of heavy metal Cu ²⁺ , Pb ²⁺ , Cd ²⁺ or Zn ²⁺ in water is greater than 100mg/L, it is counted as 100mg/L n times of L, n is a positive integer, and the adsorbent is added to the water body at the ratio of ng:500ml (after the adsorption equilibrium is reached, the adsorption and removal rates of the four metals in the water body can reach 80%, 80%, 50%, 50% respectively. %above).

The dynamic adsorption mode can be used in actual engineering applications. According to the actual concentration of heavy metals in sewage and the purification requirements of polluted water bodies, the adsorption columns are operated in series, and the single-column adsorption residence time is 12 hours until the discharge standard is reached. After the adsorbent is saturated, it can be taken out for regeneration of the adsorbent.

The adsorbent regeneration process is:

(1) Separate, wash and collect the saturated heavy metal adsorbent by vacuum filtration, soak it in 1mol/L HCl solution for desorption after drying for 24 hours, rinse the desorbed adsorbent with distilled water until it is in the solution No detection of heavy metals Cu ²⁺ , Pb ²⁺ , Cd ²⁺ , Zn ²⁺ ;

(2) Add the desorbed adsorbent to 0.1mol/L NaOH regeneration solution and oscillate for 2 hours to regenerate. After the regeneration is completed, remove the regeneration solution, wash the adsorbent with deionized water until it is neutral, and dry it for later use.

The invention broadens the resource utilization approach of waste lithium-ion batteries. From the perspective of "treating waste with waste", based on the special crystal structure properties of metal oxides in the positive electrode of waste lithium-ion batteries, the waste lithium-ion battery positive electrode has the special crystal structure properties of the metal oxide, and the positive electrode material is recycled to make the polluted water body. As for the heavy metal adsorbent, there are no related methods and application reports.

The present invention has the following characteristics:

1. Prepare water heavy metal adsorbents from the positive electrode materials of waste lithium-ion batteries, realize "using waste to treat waste, turn waste into treasure", and broaden the resource utilization of waste lithium-ion batteries.

2. The adsorbent prepared by using the positive electrode material of waste lithium-ion batteries has high efficiency and large adsorption capacity for removing heavy metals in water; it can be recycled; and the adsorption capacity comparison with other conventional heavy metal adsorbents in water is shown in the table below.

Adsorption capacity comparison table of adsorbent prepared from waste lithium-ion battery positive electrode and other adsorbents

Reference 1: Peter et al.,2012.Dual Efficiency Of Nano-Structured TiO ₂ /Zeolyte Systems In Removal Of Copper(II)And Lead(II)Ions From AqueousSolution Under Visible Light,in:Lazar,MD(Ed.) Processes in Isotopes and Molecules. Amer Inst Physics, Melville, pp. 139-143.

Reference 2: Zheng et al., 2012). Preparation of cellulose derived from corn stalk and its application for cadmium ion adsorption from aqueous solution. Carbohydr. Polym. 90(2), 1008-1015.

Reference 3: Bahadir et al., 2018. Development of cloud point extraction preconcentration of cadmium and lead in solid samples using flame atomic absorption spectrometry. Desalin. Water Treat. 124, 193-201.

Reference 4: Feng et al., 2017. Simple fabrication of easy handling millimeter-sized porous attapulgite/polymer beads for heavy metal removal. Journal of Colloid and Interface Science 502, 52-58.

Reference 5: Zeng et al., 2015. Adsorption of Cd(II), Cu(II) and Ni(II) ions by cross-linking chitosan/rectorite nano-hybrid composite microspheres. Carbohydr. Polym. 130, 333-343.

Reference 6: Sun et al., 2016. Characterization of citric acid-modified clam shells and application for aqueous lead(II) removal. Water, Air, & SoilPollution 227(9), 298.

Reference 7: Mouni et al., 2011. Adsorption of Pb(II) from aqueous solutions using activated carbon developed from Apricot stone. Desalination 276(1-3), 148-153.

Reference 8: Pap et al., 2017. Utilization of fruit processing industry waste as green activated carbon for the treatment of heavy metals and chlorophenols contaminated water. Journal of cleaner production 162, 958-972.

Reference 9: Argun et al., 2009. Removal of Cd(II), Pb(II), Cu(II) and Ni(II) from water using modified pine bark. Desalination 249(2), 519-527.

3. The process of adsorbent applied to the adsorption of heavy metals in water is simple and practical.

Description of drawings

Fig. 1 is the electron micrograph of the adsorbent prepared from the waste lithium ion battery in Example 1.

Fig. 2 is the electron micrograph of the adsorbent prepared from the spent lithium ion battery after adsorbing Pb ions in Example 1.

Fig. 3 is the X-ray diffraction analysis of the adsorbent prepared from the waste lithium ion battery before and after the adsorption of Pb ions in Example 1. In the figure: LFP: Lithium Iron Phosphate; MSLFP: Adsorption 1 ^# prepared based on waste lithium iron phosphate positive electrode material; LFP-Pb: Lithium Iron Phosphate after adsorption of Pb; MSLFP-Pb: Adsorbent 1 ^# after adsorption of Pb

Fig. 4 is the regeneration performance analysis of the adsorbent prepared from the waste lithium-ion battery in Example 1.

Fig. 5 is the adsorption isotherm of the adsorbent prepared from the waste lithium ion battery in the process of adsorbing Cu ions in Example 1.

6 is an electron micrograph of the adsorbent prepared from the waste lithium ion battery in Example 2.

7 is an electron microscope image of the adsorbent prepared from the waste lithium ion battery after adsorbing Pb ions in Example 2.

Fig. 8 is the X-ray diffraction analysis of the adsorbent prepared from the waste lithium ion battery before and after the adsorption of Pb ions in Example 2. In the figure: LMO: lithium manganese oxide; MSLMO: adsorption 2 ^# prepared based on waste lithium manganate ion battery cathode material; LMO-Pb: lithium manganate material after adsorbing Pb; MSLMO-Pb: adsorbent 2 ^# after adsorbing Pb.

Fig. 9 is an analysis of the regeneration performance of the adsorbent prepared from the waste lithium-ion battery in Example 2.

Fig. 10 is the adsorption isotherm of the adsorbent prepared from the waste lithium ion battery in the process of adsorbing Cu ions in Example 2.

Detailed ways

Example 1

This example prepares the adsorbent 1 ^# based on the positive electrode material of waste lithium iron phosphate lithium ion battery

(1) Dismantling of waste lithium-ion batteries:

First cut open the aluminum-plastic casing of the waste lithium-ion battery with a knife to obtain a battery pack composed of battery cells, take out the connecting wires and solder joints, and obtain a lithium-ion battery cell. Connect the positive and negative electrodes of each cell to 3- Discharge the 5W small light bulb until the small light bulb does not light up, then put the lithium-ion battery cell discharged from the small light bulb into a saturated NaCl solution to short-circuit the positive and negative poles of the lithium-ion battery cell, and finally make the lithium-ion battery cell The body is completely discharged. Use a multimeter to detect the voltage of the discharged lithium-ion battery cell. After ensuring that the cell voltage is less than 0.3V, it is considered that the discharge process is over, and the battery cell is disassembled. Cut off the sealing ring at the positive end of the battery, remove the top gasket, cut off the wrapped aluminum shell, tear off the transparent film, and roll out the aluminum foil in a roll. The attachment (black solid attachment) on the aluminum foil is ready It is the positive electrode active material of lithium ion battery.

(2) Recycling the lithium-ion battery positive electrode material obtained by dismantling:

Cut the unfolded aluminum foil with the positive active material into pieces with a side length of 0.2-1 cm, immerse in dimethyl sulfoxide (DMSO) (mass ratio of pieces to DMSO: 1:10), shake in a water bath at 85°C for 1 hour, Dissolve the electrode binder polyvinylidene fluoride (PVDF) in DMSO solution, and then use microwave ultrasonication for 10 minutes to completely separate the positive electrode active material on the aluminum foil, take out the aluminum foil and rinse it with clean water to recover the clean aluminum foil. Under the condition of maintaining the temperature of the DMSO mixture at 85°C, filter the DMSO mixture solution with a filter membrane with a pore size of 0.45 μm to obtain the filter intercepted substance-positive electrode active material, and wash the active material with 70% ethanol and deionized water for 3 times , and then dried at a temperature of 80-100°C to obtain the precursor material of the water heavy metal adsorbent.

(3) Modification of the adsorbent precursor material:

The obtained water heavy metal adsorbent precursor material was added into a DTPA solution with a mass concentration of 0.1% at a mass volume ratio of 1 g: 5 ml, and ultrasonicated for 10 minutes to form a uniformly dispersed precursor material mixture. 1 part by volume of the precursor material mixture was slowly added dropwise to 5 parts by volume of glutaraldehyde alkaline solution (the volume ratio of 30% glutaraldehyde to 0.01M NaOH was 1:30), and reacted at room temperature for 12 hours , the obtained static precipitation product was washed several times with deionized water and ethanol, and dried in an oven at 80°C for 24 hours to obtain the modified water heavy metal adsorbent 1#.

At 25.5°C, add 0.5g of adsorbent 1# to four groups of 250ml heavy metal Cu ²⁺ , Pb ²⁺ , Cd ²⁺ , Zn ²⁺ solutions (pH7.0) with a concentration of 100mg/L. middle. Place in a constant temperature water bath shaker to oscillate for adsorption at a speed of 120 rpm. The adsorption capacities of the adsorbent 1# for heavy metals Cu ²⁺ , Pb ²⁺ , Cd ²⁺ and Zn ²⁺ were measured to be 42.5, 43.0, 27.5 and 31.0 mg/g, respectively. Under this condition, the removal rates of Cu ²⁺ , Pb ²⁺ , Cd ²⁺ , and Zn ²⁺ reached 85%, 86%, 55%, and 62% for the adsorbent 1#.

Fig. 1 has provided the electron micrograph of the adsorbent 1# prepared by this example with waste lithium iron phosphate lithium ion battery; Fig. 2 has provided the electron micrograph of the adsorbent prepared by the waste lithium iron phosphate lithium ion battery after adsorbing Pb ion; Fig. 3 is the X-ray diffraction analysis of the adsorbent prepared by the waste lithium iron phosphate lithium ion battery before and after adsorption of Pb ions in Example 1; Fig. 4 is the regeneration performance analysis of the adsorbent prepared by the waste lithium iron phosphate lithium ion battery in embodiment 1 Fig. 5 is the adsorption isotherm of the adsorbent prepared by waste lithium iron phosphate lithium ion battery in the process of adsorbing Cu ions in Example 1.

The saturated adsorbent is regenerated according to the following process:

(1) Use a vacuum filtration device to separate, wash and collect the saturated heavy metal adsorbent. After drying, soak it in 1mol/L HCl solution for desorption for 24 hours. Rinse the desorbed adsorbent several times with distilled water. Until no heavy metals Cu ²⁺ , Pb ²⁺ , Cd ²⁺ , Zn ²⁺ can be detected in the solution;

(2) Add the desorbed adsorbent to 0.1mol/L NaOH regeneration solution and oscillate for 2 hours to regenerate. After the regeneration is completed, remove the regeneration solution, wash the adsorbent with deionized water until it is neutral, and dry it for later use.

Example 2

This example prepares the adsorbent 2 ^# based on the positive electrode material of the waste lithium manganate battery

(1) Dismantling of waste lithium-ion batteries:

First cut open the aluminum-plastic casing of the waste lithium-ion battery with a knife to obtain a battery pack composed of battery cells, take out the connecting wires and solder joints, and obtain a lithium-ion battery cell. Connect the positive and negative electrodes of each cell to 3- Discharge the 5W small light bulb until the small light bulb does not light up, then put the lithium-ion battery monomer discharged from the small light bulb into a saturated NaCl solution to short-circuit the positive and negative poles of the lithium-ion battery monomer, and finally make the lithium-ion battery single The body is completely discharged. Use a multimeter to detect the voltage of the discharged lithium-ion battery cell, and disassemble the battery cell after ensuring that the cell voltage is less than 0.3V.

(2) Recycling the lithium-ion battery positive electrode material obtained by dismantling:

Cut the unfolded aluminum foil with the positive active material into fragments with a side length of 0.2-1 cm, immerse in dimethyl sulfoxide (DMSO) (mass ratio of fragments to DMSO: 1:15), shake in a water bath at 80°C for 2 hours, Dissolve the electrode binder polyvinylidene fluoride (PVDF) in DMSO, and then use microwave ultrasound for 30 minutes to completely separate the positive electrode active material on the aluminum foil, take out the aluminum foil and rinse it with clean water to recover the clean aluminum foil. Under the condition of maintaining the temperature of the DMSO mixture at 80°C, filter the DMSO mixture solution with a filter membrane with a pore size of 0.45 μm to obtain the filtered substance-positive active material, and wash the active material several times with 70% ethanol and deionized water , and then dried at a temperature of 80° C. to 100° C. to obtain the precursor material of the water heavy metal adsorbent.

(3) Modification of the adsorbent precursor material:

The obtained water heavy metal adsorbent precursor material was added to a DTPA solution with a mass concentration of 0.1% at a mass volume ratio of 1 g: 5 ml, and ultrasonicated for 15 minutes to form a uniformly dispersed precursor material mixture. 1 part by volume of the precursor material mixture was slowly added dropwise to 4 parts by volume of glutaraldehyde alkaline solution (the volume ratio of 20% glutaraldehyde to 0.01M NaOH was 1:20), and reacted at room temperature for 10 hours , the obtained static precipitation product was washed several times with deionized water and ethanol, and dried in an oven at 60°C for 24 hours to obtain the modified water heavy metal adsorbent 2#.

At 24.5°C, add 0.5g of adsorption material 2# to four groups of 250ml heavy metal Cu ²⁺ , Pb ²⁺ , Cd ²⁺ , Zn ²⁺ solutions (pH6.5) with a concentration of 100mg/L. middle. Place in a constant temperature water bath shaker to oscillate for adsorption at a speed of 110 rpm. The adsorption capacities of the adsorbent 2# for heavy metals Cu ²⁺ , Pb ²⁺ , Cd ²⁺ and Zn ²⁺ were measured to be 41.0, 42.5, 26.5 and 28.0 mg/g, respectively. Under this condition, the removal rates of Cu ²⁺ , Pb ²⁺ , Cd ²⁺ , and Zn ²⁺ reached 82%, 85%, 53%, and 56% for the adsorbent 2#.

Fig. 6 has provided the electron micrograph of the adsorbent 2# prepared by this example with the waste lithium manganate lithium ion battery; Fig. 7 has provided the electron micrograph of the adsorbent prepared by the waste lithium iron manganate lithium ion battery after the adsorption of Pb ion; Fig. 8 is the X-ray diffraction analysis of the adsorbent prepared by the waste lithium iron manganate lithium ion battery before and after adsorbing Pb ions in Example 2; Fig. 9 is the regeneration of the adsorbent prepared by the waste lithium iron manganate lithium ion battery in embodiment 2 Performance analysis; FIG. 10 is the adsorption isotherm of the adsorbent prepared from waste lithium iron manganate lithium ion battery in the process of adsorbing Cu ions in Example 2.

The saturated adsorbent was regenerated according to the procedure in Example 1.

Example 3

The difference between this embodiment and embodiment 1 is:

During the recovery process of the lithium-ion battery positive electrode material obtained by dismantling in step (2), the mass ratio of the fragments to dimethyl sulfoxide is 1:12. The shaking time is 1.5 hours. The microwave ultrasonication time is 20 minutes.

During the modification process of the adsorbent precursor material in step (3), the ultrasonic time is 30 minutes. The precursor material mixture is added to the alkaline solution of glutaraldehyde at a volume ratio of 1:4.5. The alkaline solution of glutaraldehyde is formed by mixing 25% glutaraldehyde solution and 0.01M NaOH at a volume ratio of 1:25. The reaction time at room temperature is 11 hours. The drying is oven drying at 70° C. for 24 hours.

The present embodiment makes adsorbent 3#.

At 28°C, add 1.0g of adsorbent 3# to four groups of 250ml heavy metal Cu ²⁺ , Pb ²⁺ , Cd ²⁺ , Zn ²⁺ solutions (pH8.0) with a concentration of 200mg/L middle. Place in a constant temperature water bath shaker to oscillate for adsorption at a speed of 120 rpm. The adsorption capacities of the adsorbent 3# for heavy metals Cu ²⁺ , Pb ²⁺ , Cd ²⁺ and Zn ²⁺ were measured to be 40.5, 41.0, 26.5 and 26.0 mg/g, respectively. Under this condition, the removal rates of Cu ²⁺ , Pb ²⁺ , Cd ²⁺ , and Zn ²⁺ reached 81%, 82%, 53%, and 52% for the adsorbent 3#.

Claims (6)

1. A method for reclaiming waste lithium-ion battery cathode material to prepare heavy metal adsorbent, is characterized in that: comprise the following steps: (1) Dismantling of waste lithium-ion batteries: Obtain the battery pack from the shell of the waste lithium-ion battery, take out the connecting wires and solder joints of the battery pack to obtain a lithium-ion battery; discharge each battery; then put the discharged lithium-ion battery into a saturated NaCl solution, Short-circuit the positive and negative poles of the lithium-ion battery monomer, and finally fully discharge the lithium-ion single battery, then disassemble the single battery, and unfold the rolled aluminum foil. The attached state on the aluminum foil is the positive electrode material of the lithium-ion battery; (2) Recycling of positive electrode materials of lithium-ion batteries obtained from dismantling: Cut the expanded aluminum foil with the positive electrode active material into pieces, immerse in dimethyl sulfoxide, shake at a constant temperature in a water bath, dissolve the electrode binder in dimethyl sulfoxide, and then treat the positive electrode on the aluminum foil with ultrasonic waves. The active material is completely separated, and the aluminum foil is taken out and rinsed with clean water to obtain a clean aluminum foil; After the aluminum foil is taken out, the dimethyl sulfoxide mixed solution dissolved with the electrode binder is oscillated under the condition of maintaining a constant temperature of 80±5°C in a water bath, and filtered through a filter membrane with a pore size of 0.45 μm to obtain the positive electrode active material. Wash with 70% ethanol and deionized water successively, and dry to obtain the water heavy metal adsorbent precursor material; (3) Modification of the adsorbent precursor material: Add the obtained water heavy metal adsorbent precursor material into a DTPA solution with a mass concentration of 0.1%, and perform ultrasonic treatment to form a uniformly dispersed precursor material mixture; Slowly add the precursor material mixture to the alkaline solution of glutaraldehyde, react at room temperature, wash the obtained static precipitation product with deionized water and ethanol, and dry to obtain a modified water heavy metal adsorbent; The side length of the fragments in the step (2) is 0.2-1 cm, the mass ratio of the fragments to dimethyl sulfoxide is 1:10-15, the oscillation time is 1-2 hours, and the microwave ultrasonic time is 10-30 minutes, the drying temperature is 80-100°C; In the step (3), the water heavy metal adsorbent precursor material is added to the DTPA solution at a mass volume ratio of 1g:5ml, the ultrasonic time is 10-30 minutes, and the precursor material mixture is 1:4～ The volume ratio of 5 is added to the alkaline solution of glutaraldehyde, and the alkaline solution of glutaraldehyde is formed by mixing 20-30% glutaraldehyde solution and 0.01M NaOH in a volume ratio of 1:20-30, and the reaction at room temperature The time is 10-12 hours, and the drying is oven drying at 60-80° C. for 24 hours. 2. The method for preparing heavy metal adsorbents by recycling waste lithium-ion battery cathode materials according to claim 1, characterized in that the process of discharging each single cell in the step (1) is: positive and negative for each single cell The electrode is connected to a 3-5W small bulb to discharge until the small bulb goes out. 3. The method for preparing a heavy metal adsorbent by reclaiming waste lithium-ion battery cathode materials according to claim 1, wherein the complete discharge of the single cell in the step (1) refers to detecting the voltage of the discharged lithium-ion single cell , to ensure that the monomer voltage is less than 0.3V. 4. The method for preparing heavy metal adsorbents by recycling waste lithium-ion battery cathode materials according to claim 1, characterized in that, the process of disassembling the single battery in the step (1) is to cut off the sealing ring at the positive end of the battery , and then remove the top gasket, cut open the wrapped aluminum shell, tear off the transparent film, and unfold the aluminum foil into a roll. The positive electrode active material of the lithium-ion battery is attached to the aluminum foil. 5. The heavy metal adsorbent prepared by the method described in any one of claims 1-4 is used to carry out adsorption treatment to Cu, Cd, Zn or Pb heavy metal polluted water: For industrial wastewater involving heavy metals, during static adsorption, first adjust the pH of the wastewater to 6-8, and determine the dosage of the adsorbent according to the concentration of heavy metals in the water: ① Heavy metals in water Cu ²⁺ , Pb ²⁺ , Cd ²⁺ or Zn ²⁺ When the concentration is lower than 50mg/L, the adsorbent is added to the water body at a ratio of 1g:1000ml; ②When the concentration of heavy metal Cu ²⁺ , Pb ²⁺ , Cd ²⁺ or Zn ²⁺ in the water is 50-100mg/L, the adsorption 3. When the concentration of heavy metal Cu ²⁺ , Pb ²⁺ , Cd ²⁺ or Zn ²⁺ in water is greater than 100 mg/L, it is counted as n times of 100 mg/L, and n is positive Integer, the adsorbent is added to the water body according to the ratio of ng:500ml; After the adsorbent is saturated, it is taken out for regeneration of the adsorbent. 6. The heavy metal adsorbent according to claim 5 is used to carry out adsorption treatment to Cu, Cd, Zn or Pb heavy metal polluted water body, it is characterized in that, described adsorbent regeneration process is: (1) Separate, wash and collect the saturated heavy metal adsorbent by vacuum filtration, soak it in 1mol/L HCl solution for desorption after drying for 24 hours, rinse the desorbed adsorbent with distilled water until it is in the solution No detection of heavy metals Cu ²⁺ , Pb ²⁺ , Cd ²⁺ , Zn ²⁺ ; (2) Add the desorbed adsorbent to 0.1mol/L NaOH regeneration solution and oscillate for 2 hours to regenerate. After the regeneration is completed, remove the regeneration solution, wash the adsorbent with deionized water until it is neutral, and dry it for later use.

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